Orthopedic Fixation Devices and Methods of Installation Thereof

ABSTRACT

Orthopedic fixation devices and methods of installing the same. The orthopedic fixation device may include a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element and a retention member is configured to allow polyaxial rotation of the bone fastener and also to lock the bone fastener in place upon application of a force on a saddle and clamp in the coupling element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part application of U.S. patentapplication Ser. No. 15/193,289 filed on Jun. 27, 2016, which is acontinuation in part application of U.S. patent application Ser. No.14/514,796 filed on Oct. 15, 2014, which is a divisional of U.S. patentapplication Ser. No. 13/183,965 filed on Jul. 15, 2011 (now issued asU.S. Pat. No. 8,888,827), the contents of all of which are incorporatedby reference herein in their entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates to orthopedic fixation devices, and, inone or more embodiments, to an orthopedic fixation device configured forloading of the bone fastener from the bottom of the tulip element.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. Often, these irregularities are treated byimmobilizing a portion of the spine. This treatment typically involvesaffixing a plurality of fixation devices to one or more vertebrae andconnecting the devices to an elongate rod that generally extends in thedirection of the axis of the spine.

Treatment for these spinal irregularities often involves using a systemof fixation devices to attain stability between spinal segments.Instability in the spine can create stress and strain on neurologicalelements, such as the spinal cord and nerve roots. In order to correctthis, implants of certain stiffness can be implanted to restore thecorrect alignment and portion of the vertebral bodies. In many cases, afixation device along with a vertical solid member can help restorespinal elements to a pain free situation, or at least may help reducepain or prevent further injury to the spine.

Typically, fixation devices may include a bone fastener (e.g., bonescrew, hook, etc.) for coupling the fixation device to vertebra.Fixation devices further may include a tulip element for coupling thebone fastener to the elongated rod. Clamp and/or wedge elements may beused to secure the bone fastener in the tulip element. A locking cap maybe used to secure the rod in the tulip element. While these designs canbe used in the treatment of spinal irregularities, they typicallyrequire loading of the bone fastener from the top of the tulip element.One drawback to this top-loading design is that different sizes of thetulip element must be used based on the diameter of the bone fastener toaccommodate passage of the fastener through the tulip element, as theinner bore of the tulip element will generally need to be larger thaneither the combined size of the bone fastener head and clamp element orthe bone fastener diameter. Another drawback to this top-loading designis that bone hooks cannot be used as they will generally not passthrough the tulip element. Yet another drawback to this top-loadingdesign is that bone fastener must be installed in the bone whileattached to the tulip element.

Accordingly, there exists a need for new and improved orthopedicfixation devices.

SUMMARY OF THE INVENTION

In an exemplary embodiment, the present disclosure provides anorthopedic fixation device including a coupling element, wherein thecoupling element comprises a bore there through, a bone fastener,wherein the bone fastener comprises a head and an extension that extendsfrom the head, wherein the head is configured for loading into thecoupling element through the bottom of the bore. The orthopedic fixationdevice may also include a clamp configured to receive the head of thebone fastener, a saddle configured to engage the clamp and disposed onthe clamp, and a retention member configured to engage the clamp,wherein the retention member includes an undulated top surface and anundulated bottom surface and further configured to be disposed in anindentation within the coupling element. The device may also, uponapplication of a force on top of the saddle, be configured such that thesaddle presses the clamp to engage a tapered surface of the retentionmember to lock the coupling element to the bone fastener, and prior tothe application of the force, the coupling element may be moved in apolyaxial manner with respect to the bone fastener.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred or exemplary embodiments of the invention, areintended for purposes of illustration only and are not intended to limitthe scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an exploded view of an orthopedic fixation device inaccordance with embodiments of the present invention;

FIG. 2 is a perspective view of a locking clamp assembly in accordancewith embodiments of the present invention;

FIG. 3 is a cross-sectional view of a locking clamp assembly inaccordance with embodiments of the present invention;

FIG. 4 is a top view of a wedge element in accordance with embodimentsof the present invention;

FIG. 5 is a side view of a wedge element in accordance with embodimentsof the present invention;

FIG. 6 is a cross-sectional view of a locking clamp assembly disposed ina tulip element in an unlocked configuration in accordance withembodiments of the present invention;

FIG. 7 is a cross-sectional view of a locking clamp assembly disposed ina tulip element in a locked configuration in accordance with embodimentsof the present invention;

FIG. 8 is a top view of a tulip element in accordance with embodimentsof the present invention;

FIG. 9 is a top view of a locking cap assembly in accordance withembodiments of the present invention;

FIG. 10 is a perspective view of a locking cap assembly in accordancewith embodiments of the present invention;

FIG. 11 is a cross-sectional view of a locking cap assembly inaccordance with embodiments of the present invention;

FIGS. 12-14 illustrate an alternative orthopedic fixation device inaccordance with embodiments of the present invention;

FIGS. 15-16 illustrate another alternative orthopedic fixation device inaccordance with embodiments of the present invention;

FIGS. 17-19 illustrate yet another alternative orthopedic fixationdevice in accordance with embodiments of the present invention;

FIGS. 20-22 illustrate yet another alternative orthopedic fixationdevice in accordance with embodiments of the present invention;

FIG. 23 illustrates an orthopedic fixation device comprising a bone hookin accordance embodiments of the present invention;

FIGS. 24-25 illustrate an alternative wedge element in accordance withembodiments of the present invention;

FIG. 26 illustrates an offset iliac connector in accordance withembodiments of the present invention;

FIGS. 27-29 illustrate a bone fastener having a threaded instrumentinterface in accordance with embodiments of the present invention; and

FIG. 30 illustrates a cross-sectional view of a vertebra having anorthopedic fixation device installed therein in accordance withembodiment of the present invention.

FIG. 31 illustrates a fixation device consistent with the presentdisclosure.

FIG. 32 illustrates a fixation device consistent with the presentdisclosure.

FIG. 33 illustrates a fixation device consistent with the presentdisclosure.

FIG. 34 illustrates a fixation device consistent with the presentdisclosure.

FIG. 35 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the present disclosure.

FIG. 36 illustrates a cross-sectional view of the fixation device ofFIG. 35 consistent with the principles of the present disclosure.

FIG. 37 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the principles of the present disclosure.

FIG. 38 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the principles of the present disclosure.

FIG. 39 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the principles of the present disclosure.

FIG. 40 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the principles of the present disclosure.

FIG. 41 illustrates a cross-sectional view of an exemplary fixationdevice consistent with the principles of the present disclosure.

FIG. 42A illustrates a cross-sectional views of an exemplary couplingelement consistent with the principles of the present disclosure.

FIG. 42B illustrates a cross-sectional view of an exemplary retentionmember consistent with the principles of the present disclosure.

FIG. 43A illustrates a cross-sectional views of an exemplary couplingelement consistent with the principles of the present disclosure.

FIG. 43B illustrates a cross-sectional view of an exemplary retentionmember consistent with the principles of the present disclosure.

FIGS. 44A-44B illustrate the retention member of FIG. 43B consistentwith the principles of the present disclosure.

FIGS. 45A-45B illustrate an exemplary retention member consistent withthe principles of the present disclosure.

FIGS. 46A-46B illustrate an exemplary retention member consistent withthe principles of the present disclosure.

FIGS. 47A-47B illustrate an exemplary retention member consistent withthe principles of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are generally directed toorthopedic fixation devices configured for bottom loading of the bonefastener. Instead of loading the bone fastener from the top of the tulipelement, embodiments of the present invention load the bone fastenerfrom the bottom of the tulip element. With the bone fastener loaded inthe tulip element, a locking clamp assembly can then be used to securethe bone fastener therein. Thus, unlike prior orthopedic fixationdevices, embodiments of the present invention permit the use of largerbone fasteners without having to also increase the size of the tulipelement. This should, for example, reduce the needed inventory,decreasing the necessary graphic cases needed to perform a similarprocedure, while decreasing in-house inventory costs.

Further, as explained by the examples and illustrations below, the bonefastener of the orthopedic fixation devices can be placed in thevertebra without the tulip element in accordance with embodiments of thepresent invention. The tulip element can then be attached to the bonefastener in situ. This should reduce the material in the surgical wound,thus increasing visualization for disc preparation and interbodyprocedures, for example. The bone fastener can also be used to distractor otherwise manipulate the surgical site, further increasingvisualization and ease of surgery, for example. Additionally, sitepreparation can be performed, in some embodiments, after the bonefastener has been placed, which may allow for more accurate pedicledecortication.

Turning now to FIG. 1, an exploded view of an orthopedic fixation device2 is illustrated in accordance with embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 may comprisea bone fastener 4, a locking clamp assembly 6 (which may comprise, forexample, a clamp element 7 and a wedge element 8), a tulip element 10,and a locking cap assembly 12. As will be discussed in more detailbelow, the bone fastener 4 may be loaded from the bottom of the tulipelement 10 with the locking clamp assembly 6 already loaded therein.Prior to being locked into place, the tulip element 10 can be moved androtated into a plurality of positions with respect to the bone fastener4. Once the tulip element 10 is at the desired position with respect tothe bone fastener 4, the tulip element 10 may be locked onto the bonefastener 4. In the illustrated embodiment, the locking cap assembly 12is configured to secure a rod 14 in the tulip element 10. In oneembodiment, the tulip element 10 is fixed onto the bone fastener 4contemporaneously with securing of the rod 14 in the tulip element 10.

As illustrated by FIG. 1, the bone fastener 4 includes a head 16 and ashaft 18 that extends from the head 16. The illustrated embodiment showsthe shaft 18 having a tapered shape and threads 20. Those of ordinaryskill in the art will appreciate that the shaft 18 may have a number ofdifferent features, such as thread pitch, shaft diameter to threaddiameter, overall shaft shape, and the like, depending, for example, onthe particular application. While the head 16 may have any generalshape, at least a portion of the head 16 may have a curved surface inorder to allow for rotational movement or angular adjustment of the bonefastener 4 with respect to the tulip element 10. For example, at least aportion of the head 16 may be shaped to form a portion of a ball or atleast a portion of a sphere. As illustrated, the head 16 may have aroughened or textured surface 22 that improves engagement with the clampelement 7. In certain embodiments, the head 16 may have a toolengagement surface, for example, that can be engaged by a screw-drivingtool or other device. The tool engagement surface can permit thephysician to apply torsional or axial forces to the bone fastener 4 todrive the bone fastener 4 into the bone. In the illustrated embodiment,the tool engagement surface of the head 16 is a polygonal recess 24. Forinstance, the polygonal recess 24 may be a hexagonal recess thatreceives a hexagonal tool, such as an allen wrench, for example. Thepresent invention is intended to encompass tool engagement surfaceshaving other shapes, such as slot or cross that may be used, forexample, with other types of screwdrivers. In an alternative embodiment(not illustrated), the engagement surface may be configured with aprotruding engagement surface that may engage with a tool or devicehaving a corresponding recess.

Referring now to FIGS. 1-3, clamp element 7 of the locking clampassembly 6 will be described in more detail in accordance withembodiments of the present invention. As illustrated, the clamp element7 includes a first clamp portion 26 and a second clamp portion 28. Inthe illustrated embodiment, the first clamp portion 26 is substantiallyidentical to and a mirror image of, the second clamp portion 28. Thefirst and second clamp portions 26, 28 provide a collar about the head16 of the bone fastener 4, when installed, as discussed in more detailbelow. The first and second clamp portions 26, 28 grip bone fastener 4when force is applied onto the clamp element 7 by the tulip element 10.While the embodiments that are described and illustrated generallydescribe the first and second clamp portions 26, 28 as substantiallyidentical, the portions 26, 28 may be of varying size and are notrequired to be mirror images of one another. In addition, while theclamp element 7 is illustrated as having two clamp portions (first andsecond clamp portions 26, 28), the clamp element 7 may comprise morethan two portions for gripping the bone fastener 4.

As illustrated, each of the first and second clamp portions 26, 28includes an outer surface 30, 32, which may be curved or rounded, asbest shown in FIGS. 1 and 2. The outer surfaces 30, 32 of the first andsecond clamp portions 26, 28 may each include an outer tapered surface34, 36. In addition, the outer surfaces 30, 32 may each also have atleast one slit 38 formed therein. The at least one slit 38 may, forexample, allow the first and second clamp portions 26, 28 to constrictand securely engage the head 16 of the bone fastener 4. The outersurfaces 30, 32 should abut and engage the inner wedge surface 86 of thetulip element 10 when fully installed and locked in place in the tulipelement 10 in accordance with present embodiments. With particularreference to FIG. 3, the first and second clamp portions 26, 28 eachinclude inner surfaces 38, 40. When fully installed and locked in placein the tulip element 10, the inner surfaces 38, 40 should abut andengage the head 16 of the bone fastener 4 in accordance with presentembodiments. The illustrated embodiment shows the inner surfaces 38, 40having roughened or textured features 22 that improve engagement withthe head 16 of the bone fastener 4. The first and second clamp portions26, 28 each may also include an external lip 46, 48, which may belocated above the outer tapered surfaces 34, 36, as best seen in FIG. 3.The first and second clamp portions 26, 28 each may also include anupper surface 31, 33, as best seen in FIG. 1.

Referring now to FIGS. 1-5, the wedge element 8 of the locking clampassembly 6 will be described in more detail in accordance withembodiments of the present invention. As illustrated, the wedge element8 may include a bore 50. The lower portion of the bore 50 may be sizedto receive the upper portion of the clamp element 7, including externallips 46, 48 of the first and second clamp portions 26, 28. The wedgeelement further may include an outer surface 52 having a recessedportion 54. The outer surface 52 may be generally rounded, for example.As best seen in FIG. 4, the outer surface 52 of the wedge element 8 maybe generally elliptical, in one embodiment. The elliptical shape of theouter surface 52 should, for example, limit radial motion of the wedgeelement when installed in the tulip element 10. The wedge element 8further may include an upper surface 56. In the illustrated embodiment,the upper surface 56 defines a seat that receives the rod 14. Asillustrated, the upper surface 56 may be generally convex in shape. Inthe illustrated embodiment, the wedge element 8 further includes anupper lip 57.

With particular reference to FIG. 3, the wedge element 8 furtherincludes an inner wedge surface 58. As illustrated, the inner wedgesurface 58 may be disposed around a lower portion of the bore 50. In oneembodiment, the inner wedge surface 58 forms a conical wedge. The innerwedge surface 58 operates, for example, to engage the outer taperedsurfaces 34, 36 of the first and second clamp portions 26, 28 to forcethe clamp element 7 down the bore 62 of the tulip element 10. The wedgeelement 8 further may include an inner protruding surface 60 adjacent tothe inner wedge surface 58 and an inner recessed surface 62 adjacent theinner protruding surface 60. The wedge element 8 further may include aninner seat 64. As illustrated, the inner seat 64 may be downwardlyfacing for receiving upper surfaces 31, 33 of the first and second clampportions 26, 28. In an embodiment, the inner seat 64 restricts or limitsmovement of the clamp element 4 through the bore 50 of the wedge element8.

In accordance with present embodiments, the locking clamp assembly 6 canbe assembled prior to insertion into the tulip element 10. In oneembodiment, for assembly, the clamp element 7 may be inserted into thewedge element 8 upwardly through the bore 50. The outer surfaces 30, 32of the first and second clamp portions 26, 28 should slidingly engagethe inner wedge surface 58 of the wedge element 8 as the clamp element 7is inserted. The clamp element 7 should be inserted until the externallips 46, 48 of the first and second clamp portions 26, 28 pass the innerprotruding surface 60 of the wedge element 8. The inner protrudingsurface 60 engages the external lips 46, 48 to secure the clamp element7 in the wedge element 8. In the illustrated embodiment, the lockingclamp assembly 6 will not fit downwardly through the top of the bore 62of the tulip element 10 as the locking clamp assembly has an outerdiameter at its biggest point that is larger than the inner diameter ofthe upper portion of the bore 62.

Referring now to FIGS. 1 and 6-8, the tulip element 10 will be describedin more detail in accordance with embodiments of the present invention.As illustrated, the tulip element 10 may comprise bore 62, a body 65 andarms 66 that extend upwardly from the body 65. In the illustratedembodiment, the arms 66 define a U-shaped channel 68 sized to receivethe rod 14. Each of the arms 66 has an interior surface 70 the interiorsurface 70 having a threaded portion 72 for engaging correspondingthreads on a screw-driving tool (e.g., tool 144 on FIGS. 27-29). Theinterior surface 70 of each of the arms 66 further may include a slot 74for receiving corresponding tabs 96 (e.g., FIG. 9) of the locking capassembly 12 and a recessed surface 76 for engaging correspondingprotuberances 100 (e.g., FIG. 9) of the locking cap assembly 12. Asillustrated, the recessed surface 76 of each of the arms 66 may belocated above the slot 74. The interior surface 70 of each of the arms66 further may include a protuberance 78. In the illustrated embodiment,the protuberance 78 of each of the arms 66 is located below the threadedportion 72 with the threaded portion 72 being located between theprotuberance 78 and the slot 74. As best seen in FIG. 6, the interiorsurface 70 of each of the arms 66 further may form a downwardly facingseat 79, for example, which may limit or restrict movement of thelocking clamp assembly 6 through the bore 62. Each of the arms 66further may include an outer surface 80. The outer surface 80 of each ofthe arms 66 may include a tool engagement groove 82 formed on the outersurface 80 which may be used for holding the tulip element 10 with asuitable tool (not illustrated).

As illustrated, the body 65 of the tulip element 10 may have an outersurface 84, which may be curved or rounded, as best seen in FIG. 1. Withparticular reference to FIGS. 6 and 7, the body 65 further may includean inner wedge surface 86 disposed around a lower portion of the bore62. In one embodiment, the inner wedge surface 86 forms a conical wedge.The inner wedge surface 86 of the body 65 of the tulip element 10, forexample, may abut and engage the outer surfaces 30, 32 of the first andsecond clamp portions 26, 28 when the locking clamp assembly 6 is fullyinstalled and locked in place.

In accordance with present embodiments, the locking clamp assembly 6 maybe installed in the tulip element 10 in either an unlocked position or alocked position. FIG. 6 illustrates the locking clamp assembly 6disposed in the tulip element 10 in the unlocked position in accordancewith embodiments of the present invention. In FIG. 6, the locking clampassembly 6 has been inserted into the tulip element 10 upwardly throughthe bore 62. The locking assembly 6 should be inserted until the upperlip 57 of the wedge element 8 passes the protuberances 78 located on theinterior surfaces 70 of the arms 66 of the tulip element 10. Theprotuberances 78 should engage the upper lip 57 to secure the lockingclamp assembly 6 in the tulip element 10. While not illustrated on FIG.6, the bone fastener 4 (e.g., shown on FIG. 1) can now be placed intothe locking assembly 6 through a snap fit with the clamp element 7.There should be sufficient clearance for the clamp element 7 to expandand snap around the head 16 of the bone fastener 4. The locking clampassembly 6 and the tulip element 10, however, should still be free torotate with respect to the bone fastener 4. The tulip element 10 can bemoved and rotated to obtain a desired portion with respect to the bonefastener 4. The locking clamp assembly 6 should also move with the tulipelement during rotation of the tulip element 10 with respect to the bonefastener 4. Once the tulip element 10 is at the desired position, thetulip element 10 may be locked onto the bone fastener 4. The lockingclamp assembly 6 and the tulip element 10 should cooperate to lock theclamp assembly 6 onto the head 16 of the bone fastener 4.

FIG. 7 illustrates the locking clamp assembly 6 disposed in the tulipelement 10 in the locked position in accordance with embodiments of thepresent invention. In FIG. 7, the locking clamp assembly 6 has beenpushed downwardly in the bore 62 of the tulip element 10. Asillustrated, the locking clamp assembly 6 has been pushed downward untilthe upper lip 57 of the wedge element 8 passes the protuberances 78located on the interior surfaces 70 of the arms 66 of the tulip element10. As the locking clamp assembly 6 moves downward, the clamp element 7engages the body 65 of the tulip element 10. As illustrated, the outersurfaces 30, 32 of the first and second clamp portions 26, 28 of theclamp element 7 should abut and engage the inner wedge surface 86 of thebody 65 of the tulip element 10, forcing inner surfaces 38, 40 of thefirst and second clamp portions 26, 28 to engage head 16 of the bonefastener 4 (e.g., FIG.1). In the locked position, tulip element 10should be locked onto the bone fastener 4, thus preventing furtherpositioning of the tulip element 10 with respect to the bone fastener 4.

Referring now to FIGS. 1 and 9-11, the locking cap assembly 12 will bedescribed in more detail in accordance with embodiments of the presentinvention. As illustrated, the locking cap assembly 12 may comprise abody 88 and a set screw 90 threaded into a bore 92 in the body 88. Theset screw 90 may have a length, for example, that is longer than thelength of the bore 92. In the illustrated embodiment, at least a portionof the set screw 90 extends from the top of the body 88. In certainembodiments, the set screw 90 may have a tool engagement surface, forexample, that can be engaged by a screw-driving tool or other device.The tool engagement surface can permit the physician to apply torsionalor axial forces to the set screw 90 to advance the set screw 90 throughthe body 88 and onto the rod 14. When the locking cap assembly 12 is inits locked position, the set screw 90 can be advanced through the body88 to engage the rod 14, applying downward force onto the rod 14 andsecuring it to the tulip element 12. In one embodiment, the set screw 90forces the rod 14 downward and into contact with the locking clampassembly 6 causing the locking cap assembly 6 to move downward in thetulip element 10. In the illustrated embodiment, the tool engagementsurface of the set screw 90 is a polygonal recess 94. For instance, thepolygonal recess 94 may be a hexagonal recess that receives a hexagonaltool, such as an allen wrench, for example. The present invention isintended to encompass tool engagement surfaces having other shapes, suchas slot or cross that may be used, for example, with other types ofscrewdrivers. In an alternative embodiment (not illustrated), theengagement surface may be configured with a protruding engagementsurface that may engage with a tool or device having a correspondingrecess.

In accordance with present embodiments, the body 88 may have one or moreprojections. For example, the body 88 may comprise lower tabs 96projecting radially from a lower end of the body 88. In the illustratedembodiment, the body 88 comprises a pair of lower tabs 96 located onopposite sides of the body 88. As illustrated, the lower tabs 96 mayeach have an outer surface 98 that is generally rounded in shape. Inaddition, while the body 88 is illustrated as having two lower tabs 96,the body 88 may comprise more than two lower tabs 96. As illustrated,the body 88 further may comprise protuberances 100. The protuberances100 may engage with corresponding recessed surface 76 (e.g., FIG. 10) ofthe arms 66 of the tulip element 10. The protuberances 100 may becapable of providing a tactile or audible signal to the physician, suchas a click that may be felt or heard, when the locking cap assembly 12has reached its locking position. The protuberances 100 also may assistin maintaining the locking cap assembly 12 in its locked position. Inthe illustrated embodiment, the body 88 further may comprise toolengagement features. The tool engagement features may, for example, beused for holding or manipulating the locking cap assembly 12 with asuitable tool (not illustrated). In the illustrated embodiment, thelocking cap assembly 12 includes upper tabs 102. As illustrated, thetabs 102 may be formed at the upper surface of the body 88. In theillustrated embodiment, the locking cap assembly 12 includes four uppertabs 102 at the corners of the upper surface. In addition, while thebody 88 is illustrated as having four upper tabs 102, the body 88 maycomprise more or less than four upper tabs 102.

To place the locking cap assembly 12 onto the tulip element 10, thelower tabs 96 should be aligned with the u-shaped channel 68 formed bythe arms 66 of tulip element 10 and the locking cap assembly 12 can thenbe lowered downward into the bore 62 in the tulip element 10. Once thelower tabs 96 are aligned with the corresponding slots 74 in the arms 66of the tulip element 10, the locking cap assembly 12 can be rotated. Theslots 74 allow the lower tabs 96 to pass through the arms 66 when thelower tabs 96 and the slots 74 are aligned. The length of the slots 74generally correspond to the amount of rotation needed to move thelocking cap assembly 12 into or out of a locked position. In oneembodiment, the locking cap assembly 12 rotates from about 60° to about120° for placement into a locking positions, alternatively, about 80° toabout 100°, and, alternatively, about 90°. As previously mentioned, theprotuberances 100 can be configured to provide a tactile or audiblesignal to the physician when the locking cap assembly 12 has reached itslocked assembly. In addition, the protuberances 100 can also assist inmaintaining the locking cap assembly 12 in its locked position. Otherfeatures such as undercuts and geometric mating surfaces may be used toprevent rotation in the opposite direction. With the locking capassembly 12 locked in place, the set screw 94 can then be rotated. Asthe set screw 94 moves downward and extends from the bottom of the base88 of the locking cap assembly 12, the set screw 94 presses against therod 14 securing it in the tulip element 10. In addition, the rod 14 mayalso be pressed downward into engagement with the locking clamp assembly6 forcing it downward in the tulip element 10. As the locking clampassembly 6 moves downward, the clamp element 7 engages the body 65 ofthe tulip element 10. As best seen in FIG. 7, the outer surfaces 30, 32of the first and second clamp portions 26, 28 of the clamp element 7should abut and engage the inner wedge surface 86 of the body 65 of thetulip element 10, forcing inner surfaces 38, 40 of the first and secondclamp portions 26, 28 to engage head 16 of the bone fastener 4 andsecure it with respect to the tulip element 10.

Referring now to FIGS. 12-14, locking of the tulip element 10 onto thebone fastener 4 is illustrated in more detail in accordance withembodiments of the present invention. For the purposes of thisillustration, the locking cap element 12 (e.g., FIG. 1) is not shown.The tulip element 10 shown in FIGS. 12-14 is similar to the tulipelement 10 described previously except that the tulip element 10 doesnot include a threaded portion 72 (e.g., FIGS. 6-7) or a downwardlyfacing seat 79 (e.g., FIG. 6) in the interior surface 70 of the arms 66of the tulip element 10. FIGS. 12 illustrates the locking clamp assembly6 installed in the tulip element 10 in an unlocked position. Aspreviously mentioned, the locking clamp assembly 6 can be inserted intothe tulip element 10 upwardly through the bore 62. As shown in FIG. 12,the locking assembly 6 should be inserted until the upper lip 57 of thewedge element 8 passes the protuberances 78 located on the interiorsurfaces 70 of the tulip element 10. The protuberances 78 should engagethe upper lip 57 to secure the locking clamp assembly 6 in the tulipelement 10. As illustrated by FIG. 13, the bone fastener 4 can now beplaced into the locking assembly 6 through a snap fit with the clampelement 7. There should be sufficient clearance for the clamp element 7to expand and snap around the head 16 of the bone fastener 4. Thelocking clamp assembly 6 and the tulip element 10, however, should stillbe free to rotate with respect to the bone fastener 4. The tulip element10 can be moved and rotated to obtain a desired portion with respect tothe bone fastener 4. Once the tulip element 10 is at the desiredposition, the tulip element 10 may be locked onto the bone fastener 4.The locking clamp assembly 6 and the tulip element 10 should cooperateto lock the clamp assembly 6 onto the head 16 of the bone fastener 4.

FIG. 14 illustrates the locking clamp assembly 6 disposed in the tulipelement 10 in the locked position and clamping onto the bone fastener 4to secure the bone fastener 4 with respect to the tulip element 10 inaccordance with embodiments of the present invention. As seen in FIG.14, the locking clamp assembly 6 has been pushed downwardly in the bore62 of the tulip element 10 until the upper lip 57 of the wedge element 8passes the protuberances 78 located on the interior surfaces 70 of thearms 66 of the tulip element 10. As the locking clamp assembly 6 movesdownward, the clamp element 7 engages the body 65 of the tulip element10 such that the outer surfaces 30, 32 of the first and second clampportions 26, 28 of the clamp element 7 should abut and engage the innerwedge surface 86 of the body 65 of the tulip element 10, forcing innersurfaces 38, 40 of the first and second clamp portions 26, 28 to engagehead 16 of the bone fastener 4. In the locked position, tulip element 10should be locked onto the bone fastener 4, thus preventing furtherpositioning of the tulip element 10 with respect to the bone fastener 4.

Referring now to FIGS. 15 and 16, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. As previously mentioned, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8. Asillustrated, the clamp element 7 may include a first clamp portion 26and a second clamp portion 28. In the illustrated embodiment, the firstand second clamp portions 26, 28 each include an inner tapered surface106, 108 such that the lower portions of the first and second clampportions 26, 28 can expand when pressure is applied that constricts theupper portion of the first and second clamp portions 26, 28. Incontrast, to the wedge element 8 that was previously described,embodiments of the upper surface 56 of the wedge element 8 illustratedon FIGS. 15 and 16 do not define a seat that receives the rod 14 (e.g.,FIG. 1), but rather are generally planar with bore 50 penetrating therethrough. As illustrated, the wedge element 8 further includes an innerwedge surface 58 formed around a lower portion of the bore 50. As alsopreviously mentioned, the tulip element 10 generally may comprise a bore62, base 64, and arms 66. The inner diameter of the bore 62 in the upperportion of the tulip element 10 may be made smaller than either thecombined size of the clamp element 7 and the bone fastener 4 or thediameter of the shaft 14 of the bone fastener 4, whichever is larger. Asillustrated, the arms 66 may each comprise an interior surface 70. Inthe illustrated embodiment, the interior surface 70 includes innertapered surface 104 rather than a downwardly facing seat 79 (e.g., FIG.6) in the interior surface 70 of the arms 66 of the tulip element 10.

With continued reference to FIGS. 15 and 16, locking of the tulipelement 10 onto the bone fastener 4 will be described in more detail inaccordance with embodiments of the present invention. The first andsecond clamp portions 26, 28 of the clamp element 7 may be inserted oneafter another upwardly into the bore 62 of the tulip element 10. Thefirst and second clamp portions 26, 28 may be pushed axially towards thetop of the tulip element 10. The first and second clamp portions 26, 28should continue to move upwardly until they engage the inner taperedsurface 104 of the tulip element 10. Due the taper angle of the innertapered surface 104, the upper portion of the first and second clampportions 26, 28 will be forced to move inwards until the inner taperedsurfaces 106, 108 of each of the first and second clamp portions 26, 28come into contact. This contraction at the top of the first and secondclamp portions 26, 28 should result in a wider opening at the bottom ofthe clamp element 7. The bone fastener 4 can then be inserted throughthe bottom of the bore 62 of the tulip element 10 and into the clampelement 7. The bone fastener 4 can then be manipulated, for example, tocenter the clamp element 7 into the head 16 of the bone fastener 4. Thetulip element 10, however, should still be free to rotate with respectto the bone fastener 4. The tulip element 10 can be moved and rotated toobtain a desired portion with respect to the bone fastener 4. Once thetulip element 10 is at the desired position, the tulip element 10 may belocked onto the bone fastener 4.

To lock the tulip element 10, the bone fastener 4 can be pulled downwardand because the clamp element 7 is in engagement with the bone fastener4, the clamp element 7 should also move downward in the tulip element 10such that the clamp element 7 engages the body 65 of the tulip element10. As illustrated, the outer surfaces 30, 32 of the first and secondclamp portions 26, 28 of the clamp element 7 should abut and engage theinner wedge surface 86 of the body 65 of the tulip element 10, forcinginner surfaces 38, 40 of the first and second clamp portions 26, 28 toclamp onto the head 16 of the bone fastener 4. The wedge element 8 canthen be introduced downwardly from the top of the bore 62 in the tulipelement 10 to seat on top of the clamp element 7. The wedge element 8should engage the interior surfaces 70 of the tulip element 10preventing upward movement of the clamp element 7, locking the clampelement 7 in its engagement with the head 16 of the bone fastener. Inthe locked position, the tulip element 10 should be locked onto the bonefastener 4, thus preventing further positioning of the tulip element 10with respect to the bone fastener 4.

Referring now to FIGS. 17-19, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, a locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8. Theorthopedic fixation device 2 is similar to the embodiments of FIGS.15-16 except that embodiments of the wedge element 8 include downwardlyextending tabs 110 that fits into corresponding slots 112 in the top ofthe head 16 of the bone fastener 4. In general, the tabs 110 shouldimpart a uni-planar restraint on the bone fastener 4 so that it onlyslides along mating surfaces. The interior surfaces 114 of the tabs 110,best seen in FIG. 19, should forms the sides of the internal drivingfeatures. In an alternative embodiment (not illustrated), the wedgeelement 8 can be configured so that the tabs 110 are interconnected, forexample, to impart more strength to the design of the wedge element 8.

Referring now to FIGS. 20-21, an orthopedic fixation device 2 isdescribed in accordance with alternative embodiments of the presentinvention. As illustrated, the orthopedic fixation device 2 comprises abone fastener 4, a locking clamp assembly 6, and a tulip element 10. Forthe purposes of this illustration, the locking cap assembly 12 (e.g.,FIG. 1) is not shown. In the illustrated embodiment, the locking clampassembly 6 comprises a clamp element 7 and a wedge element 8.

The orthopedic fixation device 2 is similar to the embodiments of FIGS.15-16 except that embodiments of the clamp element 7 are configured fortop loading from the top of the bore 62 in the tulip element 10. Insteadof being inserted upwardly from the bottom of the bore 62, the first andsecond clamp portions 26, 28 of the clamp element 7 are inserteddownwardly from the top of the bore 62, until the clamp portions 26, 28engage the inner wedge surface 86 of the body 65 of the tulip element10. The bone fastener 4 can then be inserted upwardly from the bottom ofthe bore 62 of the tulip element 10 and into engagement with the clampelement 7 whereby the clamp element 7 will be pushed upwardly towardsthe top of the tulip element 10. The clamp element 7 will move higheruntil they engage an external temporary stop (not illustrated) thatprevents further upward movement. As the clamp element 7 moves higher inthe tulip element 10, the clamp portions 26, 28 adjust and reorient dueto increased clearance with the inner wedge surface 86 of the tulipelement 10 such that the opening at the bottom of the clamp element 7 islarger than the diameter of the head 16 of the bone fastener 4.

To lock the tulip element 10, the bone fastener 4 can be pulled downwardand because the clamp element 7 is in engagement with the bone fastener4, the clamp element should also move downward in the tulip element 10such that the outer surfaces 30, 32 of the first and second clampportions 26, 28 of the clamp element 7 should abut and engage the innerwedge surface 86 of the body 65 of the tulip element 10, forcing innersurfaces 38, 40 of the first and second clamp portions 26, 28 to clamponto the head 16 of the bone fastener 4. In accordance with presentembodiments, the smallest inner diameter for the bore 62 in the tulipelement 10 is smaller than the combined size of the clamp element 7 andthe head 16 of the bone fastener 4, when in engagement. The wedgeelement 8 can then be introduced downwardly from the top of the bore 62in the tulip element 10 to seat on top of the clamp element 7. The wedgeelement 8 should engage the interior surfaces 70 of the tulip element 10preventing upward movement of the clamp element 7, locking the clampelement 7 in its engagement with the head 16 of the bone fastener. Inthe locked position, the tulip element 10 should be locked onto the bonefastener 4, thus preventing further positioning of the tulip element 10with respect to the bone fastener 4.

Referring now to FIG. 22, an orthopedic fixation device 2 is describedin accordance with alternative embodiments of the present invention. Asillustrated, the orthopedic fixation device 2 comprises a locking clampassembly 6 and a tulip element 10. For the purposes of thisillustration, the bone fastener (e.g., FIG. 1) and locking cap assembly12 (e.g., FIG. 1) are not shown. In the illustrated embodiment, thelocking clamp assembly 6 comprises a clamp element 7 and a wedge element8.

The orthopedic fixation device 2 is similar to the embodiments of FIGS.20-21 except that embodiments of the wedge element 8 include a retentionfeature for coupling with the clamp element 7. As illustrated, the wedgeelement 8 includes an inner protruding surface 60 that engages with theexternal lips 46, 48 of the first and second clamp portions 26, 28 ofthe clamp element 7 to secure the clamp element 7 in the wedge element8. The locking clamp assembly 6 with the clamp element 7 secured in thewedge element 8 can then be inserted downwardly from the top of the bore62 in the tulip element 10, until the clamp portions 26, 28 engage theinner wedge surface 86 of the body 65 of the tulip element 10. Once thebone fastener 4 is snapped into the clamp element 7, the locking clampassembly 6 can be forced downwards through the tulip element 10 into itslocked position to secure the bone fastener (e.g., FIG. 1) in the clampelement 7. In the locked position, the tulip element 10 should be lockedonto the bone fastener 4, thus preventing further positioning of thetulip element 10 with respect to the bone fastener 4.

While the embodiments that are described and illustrated above generallyillustrate a bone fastener 4 in shape of a screw having a head 16 andshaft 18 extending there from, it should be understood that other bonefasteners may also be used such as hooks and sacral blocks. Thus, thepresent invention may be used with a wide variety of bone fasteners inaddition to a bone screw, as described above. For example, FIG. 23illustrates an embodiment in which the bone fastener 14 includes a head16 having an extension in the form of a hook 116 that extends from thehead 16. In the illustrated embodiment, the head 16 is secured in thetulip element 10 by the clamp element 7 and the wedge element 8. Asillustrated, the head 16 may have a roughened or textured surface 22that improves engagement with the clamp element 7.

FIGS. 24 and 25 illustrate a wedge element 8 having an optional rodretention feature, in accordance with embodiments of the presentinvention. In some embodiments, the rod retention feature of the wedgeelement 8 may be added to enhance retainment of the rod 14 (e.g.,FIG. 1) in a surgical procedure. In the illustrated embodiment, the rodretention feature is in the form of seat extensions 118 that will cradlethe rod 14 to retain it in the wedge element 8. As illustrated, thewedge element 8 comprises an upper surface 56 defining a seat forreceiving the rod 14. The wedge element 8 further may comprise seatextensions 118 for retaining the rod in the wedge element 8. In oneembodiment, the seat extensions 118 may be configured to flex when a rod14 is pushed down through opening 122 at the top of the seat extensions118. When pressed down, the rod 14 may engage the ends of the seatextensions 118 causing the seat extensions 118 to flex outwardincreasing the size of the opening so that the rod 14 can be moveddownwards to rest on the upper surface 56 of the wedge element 8. Inother words, the rod 14 may be snapped past the seat extensions 118 inaccordance with some embodiments. In the illustrated embodiment, thewedge element 8 further includes notches 122 to facilitate flexing ofthe seat extensions 118.

While the embodiments that are described and illustrated above generallyillustrate a tulip element 10 in the general shape of a “U” for couplingthe rod 14 to the bone fastener 4, it should be understood that any of avariety of different coupling elements may be used in accordance withembodiments of the present invention. For example, the coupling elementmay be open (e.g., tulip element 10 on FIG. 1) or closed. In someembodiments, the rod 14 may be top loaded into an open coupling element.In other embodiments, the rod 14 may be side loaded, for example, into aclosed coupling element. In some embodiments, the coupling element maybe an open, closed, or offset iliac connector. In yet other embodiments,the coupling element may be a posted screw connector. In addition, thecoupling element may be configured to move polyaxially, monoaxially, oruni-planar with respect to the bone fastener 4 prior to locking of thecoupling element onto the bone fastener 4.

FIG. 26 illustrates a coupling element in accordance with alternativeembodiments of the present invention. In the illustrated embodiment, thecoupling element is an offset iliac connector 124. The offset iliacconnector 124 should allow, for example, iliac screw placement prior toselection of coupling element type. The design of the offset iliacconnector 124 should also allow, for example, removal of the iliacconnector 124 using a specialized instrument (not illustrated) to changethe coupling element type in situ. As illustrated, the offset iliacconnector 124 includes an offset housing 126, a set screw 128, a springwasher 130, and a locking clamp assembly 132. In accordance withembodiments of the present invention, the set screw 128 can be installedthrough the bottom of the offset housing 126 and rotated (e.g., counterclockwise) until tight. After installation of the set screw 128, thespring washer 130 may then be inserted upwardly through the bottom ofthe offset housing 126. In the illustrated embodiment, the spring washer130 has a washer portion 134 and a spring portion 136 that extends downfrom the washer portion 134. The locking clamp assembly 132 may then beinserted upwardly through the bottom of the offset housing 126 andsnapped into a place, in a manner similar to the previously describedembodiments. In the illustrated embodiment, the locking clamp assembly132 includes a wedge element 138 and a clamp element 140. To engage theoffset connector with a head 16 of a bone fastener 4 (e.g., FIG. 1), theoffset connector can be pushed down onto the head 16. The head 16 of thebone fastener 4 should be pushed upward into the locking clamp assembly132. The bone fastener 4 should push the locking clamp assembly 132upward into the spring portion 136 of the spring washer 130 untilsufficient clearance is achieved between the locking clamp assembly 132and the offset housing 126 for the bone fastener 4 to snap into thelocking clamp assembly 132. The spring washer 130 should then providedownward force onto the locking clamp assembly 132 such that theinterior wedge surface 142 of the offset housing 126 applies pressure tothe locking clamp assembly 132 forcing the clamp element 138 to clamponto the head 16 of the bone fastener 4. In some embodiments, aspecialized instrument (not illustrate) can be threaded through thepolygonal recess 144 (e.g., a hexagonal recess) in the set screw 128 andinto the locking clamp assembly 132. The threading of the instrumentshould provide sufficient clearance with the offset housing 126 forremoval of the offset iliac connector 124 from the bone fastener 4without removal of the bone fastener 4 from the bone.

As previously illustrated and described with respect to FIG. 1, thetulip element 10 may include a threaded portion 72. FIGS. 27-29illustrate the threaded portion 72 of the tulip element 10 in moredetail. As illustrated, the tulip element 10 includes a body 65 and arms66. As best seen in FIG. 28, the arms 66 each include an interiorsurface 70 having a threaded portion 72. In accordance with presentembodiments, a bone fastener 4 can be secured to the tulip element 10.As illustrated, a tool 144, which may be, for example, a screw-drivingtool, can be placed through the bore 62 in the tulip element 10 and intoengagement with the tulip element 10 and the bone fastener 4. In theillustrated embodiment, the tool 144 includes a threaded portion 146that engages the threaded portion 72 of the tulip element 10. The tool144 further includes an engagement end 148 below the threaded portion 72that engages with the polygonal recess 24 (e.g., hexagonal) in the head16 of the bone fastener 4. In this manner, a rigid connection may beformed between the bone fastener 4 and the tool 144.

FIG. 30 illustrates installation of the orthopedic fixation device 2 ina vertebra 150 in accordance with embodiments of the present invention.As illustrated, the bone fastener 4 may be implanted into the vertebra150. The bone fastener 4 may then be secured to the tulip element 10using, for example, the locking clamp assembly 6. The tulip element 10can then be moved and rotated into a desired position with respect tothe bone fastener 4 and then locked onto the bone fastener 4. In oneembodiment, the tulip element 10 is fixed onto the bone fastener 4contemporaneously with securing the rod 14 to the tulip element 10 withthe locking cap assembly 12. In this manner, the rod 14 can be securedin a fixed position relative to the vertebra 150.

FIGS. 31-34 illustrate one or more alternative embodiments consistentwith the present disclosure. FIGS. 31-34 show one or more embodimentswhere the coupling element may be moved in a polyaxial direction whendisposed on a screw head but not locked in position. The screw head maybe inserted and removed through the bottom of the coupling element via abore.

FIG. 31 illustrates a cross section of an orthopedic fixation device3100 in accordance with an exemplary embodiment and comprises bonefastener 3102, a coupling element or tulip element 3104, clamp 3106,saddle 3108, and clip 3110. Bone faster 3102 may also include head 3112and shaft 3114. Bone fastener 3102 may the same or similar to bonefasteners as previously described. Fixation device 3100 may providefunctionality of locking tulip 3104 to the bone fastener 3102 byengaging a locking cap to tulip 3104. Such engagement, when a rod isdisposed in tulip 3104, may provide a force upon saddle 3108 and clamp3106 to press head 3112 against clip 3110. If the locking cap isremoved, the force upon saddle 3108 and clamp 3106 is removed, tulip3104 may be released from bone fastener 3102. In this embodiment, tulip3104 with respect to bone fastener 3102 may become polyaxial once theforce locking tulip 3104 to bone fastener 3102 is removed without anyfurther need for additional steps or manipulation.

In FIG. 31, clamp 3106 may be spherical in shape and engage with saddle3108 and head 3112. In an exemplary operation, saddle 3108 and clamp3106 may be inserted into the bottom of tulip 3104. Saddle 3108 andclamp 3106 may be designed to be separate elements or may be designed tobe coupled to one another. After saddle 3108 and clamp 3106 are insertedinto a bore 3116 at the bottom of tulip 3104, head 3112 of bone fastener3114 may be inserted into the bottom of the tulip 3104, followed by clip3110. In an exemplary embodiment, clamp 3110 and head 3112 may moveindependently of each other to provide for polyaxial movement of thetulip with respect to the bone fastener. The polyaxial movement may belocked when a locking cap is provided on the top of tulip 3104 byengaging a rod disposed in tulip 3104 and the rod presses saddle 3108downward. The downward movement of saddle 3108 presses head 3112 againstclip 3110 and thereby locking tulip 3104 to bone fastener 3102.

FIG. 32 shows another exemplary embodiment of the present disclosure.Fixation device 3200 may comprise bone fastener 3202, coupling elementor tulip element 3204, clamp 3206, and saddle 3208. Bone faster 3202 mayalso include head 3210 and shaft 3212. Bone fastener 3202 may the sameor similar to the bone fasteners already described herein. In contrastto fixation device 3100 of FIG. 31, fixation device 3200 of FIG. 32 doesnot include a clip. In operation, saddle 3208 and clamp 3206 areassembled together and inserted into the bottom of tulip 3204 to form aload position for receiving head 3210 of bone fastener 3202. Head 3210is then inserted into the bottom of tulip 3204 to be received into clamp3206. In an unlocked state, head 3210 may move independently from clamp3206 to provide for polyaxial movement of the tulip with respect to thebone fastener. Tulip 3204 may be locked to head 3210 by inserting alocking cap into the top of tulip 3204 which presses a rod disposed intulip 3204 against saddle 3208, which in turn presses against clamp 3206and head 3210 towards the bottom of tulip 3204 thereby locking tulip3204 to bone fastener 3202.

FIG. 33 shows another exemplary embodiment of the present disclosure.Fixation device 3300 may comprise bone fastener 3302, coupling elementor tulip 3304, clamp 3306, and saddle 3308. Bone fastener 3302 may alsoinclude head 3310 and shaft 3312. Bone fastener 3302 may the same orsimilar to the bone fasteners already described herein. Tulip 3304 maybe configured such that the portion of tulip 3304 receiving head 3310may be tapered. In operation, saddle 3308 and clamp 3306 are assembledtogether and inserted into the bottom of tulip 3304 to form a loadposition for receiving head 3310 of bone fastener 3302. Head 3310 isthen inserted into the bottom of tulip 3304 to be received into clamp3306. In an unlocked state, head 3310 may move independently from clamp3306 to provide for polyaxial movement of the tulip with respect to thebone fastener. Tulip 3304 may be locked to head 3310 by inserting alocking cap into the top of tulip 3304 which presses a rod disposed intulip 3304 against saddle 3308, which in turn presses against clamp 3306and head 3310 towards the bottom of tulip 3304 thereby locking tulip3304 to head 3310. The bottom of tulip 3304 contains a tapered openingconfigured to engage head 3310 to lock fixation device 3300.

FIG. 34 shows another exemplary embodiment of the present disclosure.Fixation device 3400 may comprise bone fastener 3402, tulip 3404, clamp3406, and saddle 3408. Bone fastener 3402 may also include head 3410 andshaft 3412. Bone fastener 3402 may the same or similar to the bonefasteners already described herein. Fixation device 3400 may alsoinclude a locking cap 3414 containing an inner screw 3416 and an outerscrew 3418.

In operation, saddle 3408 and clamp 3406 are assembled together andinserted into the bottom of tulip 3404 to form a load position forreceiving head 3410 of bone fastener 3412. Head 3410 is then insertedinto the bottom of tulip 3404 to be received into clamp 3406. In anunlocked state, head 3410 may move independently from clamp 3406 toprovide for polyaxial movement of the tulip with respect to the bonefastener. Tulip 3404 may be locked to head 3410 by turning outer screw3418 which is configured to engage saddle 3408. This presses saddle 3408downward, which in turn presses against clamp 3406 and head 3410 towardsthe bottom of tulip 3404 thereby locking tulip 3404 to head 3410. Innerscrew 3416 may be twisted in order to engage a rod that would bedisposed into an opening (for example, the U-shaped opening defined bytulip 3404 in FIG. 34). By twisting inner screw 3416, it engages the rodto prevent rod from moving.

FIGS. 35 and 36 illustrate another embodiment consistent with theprinciples of the present disclosure. Fixation device 3500 may comprisebone fastener 3502, tulip 3504, clamp 3506, saddle 3508, retentionmember 3510, and bore 3516. Bone fastener 3502 may also include head3512 and shaft 3514. Bone fastener 3202 may the same or similar to thebone fasteners already described herein. As with embodiments previouslydescribed, the coupling element (e.g., tulip 3504 and associatedcomponents) may be moved in a polyaxial direction when disposed on ascrew head but not locked in position. The screw head may be insertedand removed through the bottom of the coupling element via the bore.

In operation, fixation device 3500 functions in a way that is similar topreviously described fixation devices. When assembled, screw head 3512engages retention member 3510 and clamp 3506, which may be a one-piececlamp. Retention member 3510 allows for assembly of clamp 3506 and bonefastener 3502 from the bottom of tulip 3504 while maintaining a taperedlocking mechanism. It may allow the taper angle to be varied to create aself-locking or self-releasing taper without increasing assemblydifficulty.

Saddle 3508 and clamp 3506 may be first assembled into the bottom oftulip 3504, followed by retaining member 3510. A bone screw (fastener3502) may then be assembled into clamp 3506, and saddle 3508 locked intoplace creating a polyaxial screw. Tulip 3504 may be configured in amanner such that a start of a locking taper is disposed at the bottom oftulip 3504 and when retention member 3510 is disposed in tulip 3504,retention member 3510 completes the taper. Retention member 3510 may beconfigured such that it does not retain bone screw until finaltightening of a locking screw on a rod as previously described. Thisconfiguration before final tightening is shown in FIG. 35. FIG. 35 showstulip in position to accept the bone screw (i.e., prior to lockingsaddle 3508 into place). As shown in FIG. 36, upon final tightening,saddle 3508 pushes clamp 3506 down the taper created by retaining member3510 thereby locking the polyaxial motion of the bone screw (this figureshows tulip with saddle locked down meaning tulip will retain screw andscrew will be polyaxial. It is not final tightened). Under thisconfiguration by separating all or a portion of the taper from thetulip, fixation device 3500 provides a retention member that may allowfor easy assembly from the bottom of the tulip regardless of clamp sizeand/or profile, while maintaining a tapered locking mechanism. Theretention member may also allow the taper angle to be varied to create aself-locking or self-releasing taper without changing the tulip designand without increasing assembly difficulty.

Turning to FIGS. 37-42B, illustrated are various embodiments that mayhave the same or similar elements as previously described fixationdevices, including for example, FIGS. 35-36. FIGS. 37-42B alsoillustrate various exemplary embodiments of providing a separated taperfrom the tulip in the form of a retention member that may be clipped orscrewed into the bottom of the tulip.

FIG. 37 illustrates an exemplary fixation device 3700 having a retentionmember 3702. Retention member 3702 may be in the form of a threadedtapered ring that is screwed into the bottom of the tulip. For example,the tulip may contain threads 3704 that engage retention member 3702 tosecure retention member 3702 to the tulip. As previously described, thesaddle and one-piece clamp are assembled into the bottom of the tulip,followed by threading retention member 3702, in an exemplary form of asolid tapered ring, into the tulip. A bone screw can then be assembledinto the clamp, and the saddle locked into place creating a polyaxialscrew. The tulip contains the start of the locking taper, and theretention member 3702 as a threaded tapered ring, completes it.Retention member 3702 may be configured such that it does not retain thebone screw until final tightening. Upon final tightening, the clamptravels down the taper created by retention member 3102, and thepolyaxial motion of the bone screw is locked.

FIG. 38 illustrates an exemplary fixation device 3800 having a retentionmember 3802 and a groove 3804. Retention member 3802 may be in the formof an angled clip that is secured to the tulip by engaging groove 3804.In operation, the saddle and one-piece clamp are assembled into thebottom of the tulip, followed by compressing an angled clip (forexample, retention member 3802) and pressing it into the tulip. A bonescrew can then be assembled into the clamp, and the saddle locked intoplace creating a polyaxial screw. Upon final tightening, the clamptravels down the taper created by the angled clip, and the polyaxialmotion of the bone screw is locked.

FIG. 39 illustrates an exemplary fixation device 3900 having a retentionmember 3902. Retention member 3902 may be tapered ring 3904 with a clip3906. In operation, the saddle and one-piece clamp are assembled intothe bottom of the tulip. Clip 3906 may be assembled onto the taperedring 3904 as shown in FIG. 39 and then pressing retention member 3902into the tulip. A bone screw can then be assembled into the clamp, andthe saddle locked into place creating a polyaxial screw. Upon finaltightening, the clamp travels down the taper created by the retentionmember, and the polyaxial motion of the bone screw is locked.

FIG. 40 illustrates an exemplary fixation device 4000 having a retentionmember 4002. Retention member 4002 may be a tapered clip 4004 having agroove 4006. In operation, the saddle and one-piece clamp are assembledinto the bottom of the tulip. Then, retention member 4002 is pressedinto the tulip. In this example, groove 4006 may engage a portion of thetulip configured to receive 4006 such as a boss 4008. A bone screw canthen be assembled into the clamp, and the saddle locked into placecreating a polyaxial screw. Upon final tightening, the clamp travelsdown the taper created by the retention member, and the polyaxial motionof the bone screw is locked.

FIG. 41 illustrates an exemplary fixation device 4100 having a retentionmember 4102 and tulip 4104. Retention member 4102 may be a tapered clipthat has bosses 4106 that engage indentations 4108 in the bottom oftulip 4102 which are illustrated in FIGS. 42A-42B. In operation, thesaddle and one-piece clamp are assembled into the bottom of the tulip.Then, retention member 4102 is pressed into the tulip. In this example,bosses 4106 may engage indentations 4108 to secure retention member 4102to tulip 4104. A bone screw can then be assembled into the clamp, andthe saddle locked into place creating a polyaxial screw. Upon finaltightening, the clamp travels down the taper created by the retentionmember, and the polyaxial motion of the bone screw is locked.

FIGS. 43A-43B illustrates a cross-sectional view of an exemplaryretention member 4302 and tulip 4304. Tulip 4304 contains an indentation4306 that may be configured to receive retention member 4302. Retentionmember 4302 is configured to be have an undulated top surface 4308 andan undulated bottom surface 4310. FIGS. 44A-44B illustrates retentionmember 4302 in greater detail. This creates one or more peaks 4312 andvalleys 4314 on both surfaces which may create a non-planarconfiguration for retention member 4302. Indentation 4306 of tulip 4304may also be configured with corresponding valleys and peaks designed toreceive peaks 4312 and 4314. This may serve to limit rotation ofretention member 4302 when engaged with tulip 4304. In operation, thesaddle and one-piece clamp are assembled into the bottom of the tulip.Then, retention member 4302 is pressed into tulip 4304. In this example,retention member 4302 is received in indentation 4306. A bone screw canthen be assembled into the clamp, and the saddle locked into placecreating a polyaxial screw. Upon final tightening, the clamp travelsdown the taper created by the retention member, and the polyaxial motionof the bone screw is locked.

FIGS. 45A-47B illustrate other exemplary embodiments of the retentionmember. FIGS. 45A-45B show retention member 4502 with an undulatedsurface on the top and a straight surface on the bottom. FIGS. 46A-46Billustrate a retention member 4602 with undulated surfaces on the topand bottom surfaces. In this example, the undulated surface represents astraight cut as opposed to the radial cut shown in FIGS. 43B-44B. FIGS.47A-47B illustrate retention member 4702 with a single undulated surfaceon the top and a straight surface on the bottom.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. An orthopedic fixation device comprising: acoupling element, wherein the coupling element comprises a bore therethrough; a bone fastener, wherein the bone fastener comprises a head andan extension that extends from the head, wherein the head is configuredfor loading into the coupling element through the bottom of the bore; aclamp configured to receive the head of the bone fastener; a saddleconfigured to engage the clamp and disposed on the clamp; and aretention member configured to engage the clamp, wherein the retentionmember includes an undulated top surface and an undulated bottom surfaceand further configured to be disposed in an indentation within thecoupling element, wherein, upon application of a force on top of thesaddle, the saddle presses the clamp to engage a tapered surface of theretention member to lock the coupling element to the bone fastener, andwherein prior to the application of the force, the coupling element maybe moved in a polyaxial manner with respect to the bone fastener.
 2. Theorthopedic fixation device of claim 1 further comprising a locking capassembly, wherein the locking cap assembly engages a rod to secure therod to the coupling element when the locking cap assembly is locked ontothe coupling element.
 3. The orthopedic fixation device of claim 2wherein the locking cap assembly is configured to push the rod onto thesaddle to lock the coupling element to the bone fastener.
 4. Theorthopedic fixation device of claim 1, wherein the undulated top surfaceand the undulated bottom surface are a beveled cut or straight cut. 5.The orthopedic fixation device of claim 1 wherein the bore of thecoupling element is tapered.
 6. The orthopedic fixation device of claim1, wherein at least a portion of an interior surface of the couplingelement is threaded and configured to receive a locking cap.
 7. Theorthopedic fixation device of claim 1 wherein the head is shaped as asphere and the clamp has a corresponding shape to engage the head. 8.The orthopedic fixation device of claim 1 wherein the saddle has anupper surface that defines a seat for receiving a rod.
 9. The orthopedicfixation device of claim 1, further comprising a locking cap configuredto engage a threaded portion of the coupling element, said locking capcontaining an outer screw configured to engage the saddle and an innerscrew configured to engage a rod disposed in the coupling element. 10.The orthopedic fixation device of claim 1, wherein the saddle and theclamp are coupled.
 11. An orthopedic fixation device comprising: a tulipelement, wherein the tulip element comprises a body and arms that extendfrom a bore, wherein an interior surface of each arm comprises athreaded portion; a bone fastener, wherein the bone fastener comprises ahead and an extension that extends from the head, wherein the head isconfigured for loading into the tulip element through the bottom of thebore, and wherein the extension is configured for installation intobone; a clamp configured to receive the head of the bone fastener; asaddle configured to engage the clamp and disposed on the clamp; aretention member configured to engage the clamp, wherein the retentionmember includes an undulated top surface and an undulated bottom surfaceand further configured to be disposed in an indentation within thecoupling element; a locking cap configured to engage the threadedportion, wherein, upon application of a force on top of the saddle, thesaddle presses the clamp to engage a tapered surface of the retentionmember to lock the tulip element to the bone fastener, and wherein priorto the application of the force, the tulip element may be moved in apolyaxial manner with respect to the bone fastener.
 12. The orthopedicfixation device of claim 11, wherein the locking cap assembly engages arod to secure the rod to the tulip element when the locking cap assemblyis locked onto the tulip element.
 13. The orthopedic fixation device ofclaim 12 wherein the locking cap assembly is configured to push the rodonto the saddle to lock the tulip element to the bone fastener.
 14. Theorthopedic fixation device of claim 11 wherein the undulated top surfaceand the undulated bottom surface are a radial cut or straight cut. 15.The orthopedic fixation device of claim 11, wherein the bore of thetulip element is tapered.
 16. The orthopedic fixation device of claim11, wherein at least a portion of an interior surface of the tulipelement is threaded and configured to receive the locking cap.
 17. Theorthopedic fixation device of claim 11, wherein the head is shaped as asphere and the clamp has a corresponding shape to engage the head. 18.The orthopedic fixation device of claim 11, wherein the saddle has anupper surface that defines a seat for receiving a rod.
 19. Theorthopedic fixation device of claim 11, wherein the locking cap containsan outer screw configured to engage the saddle and an inner screwconfigured to engage a rod disposed in the tulip element.
 20. Theorthopedic fixation device of claim 11, wherein the saddle and the clampare coupled.